A vital sensing technology that estimates biological information of a human being is expected to be applied to, for example, not only a field of in-home healthcare or health management but also multiple types of fields such as drowsiness detection during driving, acquisition of a mental state of a user during a game, and detection of a suspicious person in a monitoring system. Currently, a main type of device that senses the biological information is used in contact with a human body and is required to be mounted by a user. Thus, the range of applications thereof is limited.
Thus, as one of measures for contactless sensing, suggested is a technology that estimates a pulse as one example of the biological information from an image acquired by capturing of a camera. Using this technology enables sensing of the biological information without causing the user to be aware thereof, and the range of applications of the technology is expected to be increased. For example, performing image processing of an image acquired by capturing along with performing capturing with a monitoring camera enables sensing of a suspicious person who has a significantly changing pulse by stress. Being able to sense a plurality of human beings represented on one camera at the same time by image processing is also a great advantage. Individual devices are not required to be prepared per user compared with a contact type, and inconvenience of attaching the device to the body can be reduced.
For example, a pulse measurement device illustrated in PTL 1 is known as a preceding technology related to the pulse estimation technology using a camera. The pulse measurement device calculates the amount of features of a captured input image, detects peak intervals of a pulse wave from the calculated amount of features, and calculates pulse rates from the detected peak intervals of the pulse wave. The pulse measurement device controls a frame rate that indicates the number of frames captured per unit time, in such a manner that the maximum estimation error between true pulse rates and pulse rates, of the calculated pulse rates, having a valid peak interval based on an adoption rate indicating the proportion of a valid peak interval is less than or equal to a defined value.
However, if the image quality of the image captured by the camera is increased (by, for example, 4K or super hi-vision (8K)), image processing of, for example, a broadcasting video content may cause a viewer to recognize the pulse rate of a human being appearing in the video content (for example, a participant), and it is difficult to properly protect the privacy of the participant.
For example, the broadcasting video content can be received and viewed with a personal computer (PC). Thus, if an application that estimates a pulse rate by above image processing is installed and used in the PC, the pulse rate of the participant may be simply recognized from an image processing result, and this is not preferable from the viewpoint of privacy.
An object of the present disclosure is to effectively reduce distribution of biological information not intended by a producer or a distributor of a video content and to properly protect the privacy of a human being appearing in the video content.